1. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue 639798 Singapore Singapore
2. Centre for Biomimetic Sensor Science; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore Singapore
3. Department of Cosmetic Sciences; Sookmyung Women's University; Yongsan-ku Seoul 140-742 Republic of Korea
4. Department of Plastic Surgery; Samsung Medical Center; Sungkyunkwan University School of Medicine; 50 Ilwon-dong Gangnam-gu Seoul 135-710 Republic of Korea
5. School of Chemical and Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive 637459 Singapore Singapore